In the current age of significant telecommunications competition, mobile network operators continuously seek new and innovative ways to create differentiation and increase profits. One of the best ways to accomplish this goal is through the delivery of highly personalized services, such as location-based services (LBS). Moreover, mobile network operators are required under the laws of certain national governments to equip their infrastructure with the ability to provide LBS, particularly having regard to emergency services. In all, there are at least four major categories of LBS, namely location-based information, location-sensitive billing, emergency services and tracking.
A popular feature of LBS is the capability to support alert-based services (ABS). In an alert-based application, registered mobile stations within the wireless network are monitored, and alerts are triggered for each mobile station based on the location of the mobile station. When an alert fires for a particular mobile station reaching or entering a predetermined location, at least one specific action is taken, such as the transmission of a message to the particular mobile station or the updating of a database. The appeal of ABS is wide-ranging, from commercial to government sectors, for the purposes of marketing, advertising, law enforcement, emergency monitoring and communication-based services, among others.
As the adoption rates of wireless LBS grow, network operators and other mobile location data providers will be required to provide an increasing amount of mobile location data to a variety of alert-based applications. These alert-based applications vary widely in their location data requirements. More specifically, some applications, such as a driving directions application or a merchant finder application, require timely data, initiated by the mobile station user. Other types of applications performing some kind of user tracking may require data only sporadically, with the delay between location requests varying as a function of mobile station position.
One of the most obvious and important aspects of ABS is positioning, i.e., the ability to determine the position of a mobile station in the network. One example of a widely recognized positioning technology is the Global Positioning System (GPS). In addition to GPS, other positioning techniques typically rely on various means of triangulation of the signal from cell sites serving a mobile station. In addition, the serving cell site can be used as a fix for location of the user.
Geographic data is another important aspect of any location system. Geographic Information Systems (GIS) provide the tools to provision and administer base map data such as man-made structures (streets, buildings) and terrain (mountains, rivers). GIS is also used to manage point-of-interest data such as location of gas stations, restaurants, nightclubs, etc. Finally, GIS information also includes information about the radio frequency characteristics of the mobile network. This allows the system to determine the serving cell site of the user.
Finally, it is not enough to be able to position the mobile user and know the map data around that position. There must also be provided a location management function to process positioning and GIS data on behalf of ABS applications. The location management function is middleware that acts as a gateway and mediator between positioning equipment and the LBS/ABS infrastructure. Among other things, the location management function may be employed to convert positioning information into useful location information and make it available for various ABS applications.
In conventional wireless networks, a request/answer mechanism involving the location management function and one or more network entities is used to determine position information regarding a mobile station in the network. Network entities that can receive location requests and thus may be involved in the request/answer mechanism include base station controllers (BSC), mobile switching centers (MSC), home location registers (HLR), visited location registers (VLR), gateway mobile location centers (GMLC), serving mobile location centers (SMLC), mobile positioning centers (MPC) and positioning determining entities (PDE), among other possibilities. The request/answer mechanism is typically implemented by leveraging the signaling that is supported by both of today's prevailing wireless network protocols, namely American National Standards Institute (ANSI)-41 and Global System for Mobility (GSM). Although the prevailing SS7 signaling is able to support this request/answer mechanism, other transport mechanisms may also be used for this purpose.
For example, the Wireless Intelligent Network (WIN) standard—also known as IS-848 and based on the ANSI-41 protocol—provides for the position of a mobile station to be obtained in the following manner. The location management function at a given service control point interrogates an HLR using a specific position request (PosReq) message. The HLR knows the last VLR that served the mobile user. Accordingly, the HLR launches a request to this VLR for position information (such as a cell site identifier) and, upon receiving this information, sends it back to the service control point in a PosReq response message.
As can be appreciated, conventional techniques require that the network be capable of specifically addressing each location request soon after it is generated. Moreover, in order for most ABS applications to be of any value, it will be necessary to request user location information at intervals of minutes or less. It is therefore apparent that the network will become increasingly, if not overly, congested as it attempts to satisfy frequent requests on behalf of each ABS application, for each user of interest. As a result, the switching and transport capacity of a wireless network will be eroded by the burdensome requirements of obtaining location information in a conventional manner.
Against this background, there is clearly a need to enable ABS applications by obtaining and using valuable location information without surpassing available bandwidth and load limits within the wireless communications network.